1. The Field of the Invention
The present invention relates to methods for functionalizing inorganic oxides such as silica. Specifically, inorganic oxides are functionalized with organic agents that are free of silicon. The functionalized inorganic oxides can be used for a variety of purposes such as supports for catalysts.
2. The Relevant Technology
Solid inorganic oxides such as silica, alumina, and other inorganic oxides are used in many different materials for a wide variety of applications. For example, silica and alumina can be used as filler materials or as supports for catalysts.
The surface properties of the inorganic oxide can be very important to the overall performance of the material. For example, the surface properties of the particle often determine how well the inorganic oxide will bond with other materials.
It is common to modify the surface of inorganic oxides to give the inorganic oxide particular properties. Inorganic oxides such as silica have been functionalized with many different types of functional groups, including carboxy, hydroxyl, thiol, amino, and other useful functional groups.
The existing methods for functionalizing solid inorganic materials with desired functional groups requires reacting the inorganic oxide (e.g., silica) with an organosilane. Organosilanes have the general formula of XSiY3 where X is a terminally functionalized organic compound and Y is an alkoxide or halide. Typically the organosilane reacts with functional groups on the surface of the inorganic material to lose Y in a condensation or substitution reaction.
Although silanes are very good functionalizing agents for functionalizing inorganic materials, silanes have limitations. One disadvantage of using silanes is the limited options for selecting the reaction conditions for carrying out the functionalization. This disadvantage can limit the types of functionalizing groups or can significantly increase the manufacturing costs, or both.
Therefore what is needed is a method of functionalizing inorganic materials with desired functional groups while avoiding the limitations and expenses of silanes.